Signal-valve device



July 3l, 1928. l 1,679,024

` 3. c. FARMER sIGNAL'vALvEDEvIcKE Filed ADem. 21, 1926 Wie-'- l l n INVENTOR .CLYDE C. FARMER ATTORN EY Patented July 3l,v 1928.

.- AUNITED sTArEsPIATENT.ePrice..

,Y l g1,679,024

CLYDE C. FARMER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOI, TO THE WESTING- HOUSE AIR BRAKE COMPANY,

F PENNSYLVANIA.

0F XLIVIERDTG, PENNSYLVANIA, A CORPORATION SIGNALvALvn DEVICE.

Application led lDecember 21, 1925'. Serial No. 156,139.

This invention relates to-signal valve devices and more particularly to a signal valve device adapte-d to be operated by'variations 1n fluid under pressure. y

.In the usual pneumatically operated signal valve device, a fiexible diaphragm, adapted to be operated by fluidunder pressure,

Tl e valve` stem being rigidly connectedr toV the diaphragm and having a close fit in the bushing, any uneven distortion of the diaphragm hasv ak tendency to cause the Avalve stem to bind in the bushing andthusrincrease ythe frictional resistance to movement of the valve stem' in the bushing,so that the valve stem is liable to stick and cause erratic action of the valve oreven failureto operate.

The principal object of my invention is to provide an improved signal valve device in which the above difficulties are overcome.

In the accompanying drawing; Fig. 1 is a cross sectionalview of a signal valve device embodying my invention; and Fig. 2 a section on the line 2-2 of Fig. `1.

According to the drawing, the signal valve device may `comprise a vcasing containing a flexible diaphragm 2 forming a chambery?) at one side, .connectedl to the usual signal pipe 4 and a chamber 5 at the opposite side. Secured axially of the diaphragm 2 at opposite sides are diaphragm plates 6 and 7, having a threaded central extension 22, eX- tending through the diaphragm and engaged by a nut 23, for clamping the plates against the diaphragm.

The clamping plate 7 is provided with a chamber 8 adapted to receive ahead 9 of a valve stem 10, said head being yieldingly held in engagement with the clamping plate 7 by a spring 11, which is held in place by a retaining member 12 having screw-threaded engagement in the plate 7.

The surface of the head 9, which engages the clampingplate 7, is made convex, and a clearance space 13 is vprovided between the retaining member 12 and the valve stem 10.

The valve stem is slidably mounted and closely fits in a bushing 14 secured in the casing 1 and isprovided with an annular groove 15 adjacent to the upper end of the bushing. From said groove to the valve seat 16 the valve stem 10 is triangular in cross-section, with the corners roundedjoff to provide three contact faces engagiugthe bore of the bushing 1li for guiding purposes, and at kthe same time the construction provides passageways connecting the annulargroove 15 with the chamber 17 said chamber being in communication with diaphragm chamber k3 by way of passage 18.

-In operation, the ksignal pipev l being charged with fluid under pressure, fluid `is supplied to the diaphragm` chamber v3 throughthe restricted passage 19 and to chamber 17 through ,passage 1,8.. From chamber` 17, fluid leaks .around thevvalve stem 10 into the diaphragm chamber 5. "The i fluid pressures are thus equalized on the op-v posite sides of the diaphragm 2 and the valve suem 10 is held with `the valve face 16 engaging the valve seat 25.v i l When the pressure in the signal pipe 4 is reduced and causes a similar reduction in thepres'sure in diaphragm chamber 3, the pressure in diaphragm chamber 5 then being higher than the pressure in chamber 3, the

fpdiaph-ragmy2'is shifted so as to movethe valve stem 10 awayfrom the valve seat'25.

This-.movement"causes the groove 15 to be uncovered, so that fiuid under ypressure can flow from thediaphragm chamber 5 past the 'valve stem 10 to lchamber 17 and thence through the choked passage 2O to passage 21 which is connected to the usual signal whistle (not shown), causing the whistle to operate in the-well known manner.

Fluid under pressure flowing from diaphragm chamber 5 to chamberl? also flows through passage 18 to the diaphragm .chamber 3. The pressure in said diaphragm chamber is also increased by flow from the signal pipe 4, as the pressure in said pipe is increased after the reduction. When the pressure of fluid in diaphragm chamber 3 again vbecomes substantially equal to the pressure in diaphragm chamber 5, the diaphragm 2 is operated to shift the valve stem 10, so that the valve facel engages the seat 25. Further flow of fluid under pres sure to passage 21 and the signal whistle is thus prevented.

Since the valve stem 10 can move relatively to the diaphragm'2 and the clamping plate y7, there will be no tendency of the loo valve stem to bind or stick in the bushing 14, as the loose mounting of the valve stem in the clamping plate 7 will permit automatie adjustment between the valve Stem and said plate, Without causing stress on the valve stem.

Having now described my invention, What l elaim as new and desire to secure by Letters Patent, is

l. A signal valve device comprising a Casing, a liexible diaphragm in said casing, a diaphragm plate carried by said diaphragm `and having a chamber, a valve, a valve stem for Said valve provided with a head mounted in said chamber, and means for holding said head in said chamber but adapted to permit movement of the head and stem relative to the diaphragm.

2. A signal valve device comprising a easing, a flexible diaphragm in said easing, a diaphragm plate carried by said diaphragm and having a chamber, a valve, a valve stem for said valve provided with a head mounted in said chamber, means for holding said head in said Chamber and adapted to `permit movement ot' the head and stem relative to the diaphragm, and means in said easing for guiding said valve stem for axial movement.

A Signal valve deviee Comprising a casing, a flexible diaphragm `mounted in said casing, a diaphragm plate carried by said diaphragm, a valve, a valve stem for said valve, a head carried by said stem and mounted in a chamber in said diaphragm plate, a spring engaging said head, and a member secured tosaid diaphragm plate for holding said spring in engagement With said head.

1 -.A signal valve device comprising a easing, a flexible diaphragm mounted in said casing, a diaphragm plate carried by `mounted in a elmmber` in said diaphragm plate, said head having a convex face engaging a Surface et' Said diaphragm plate, a spring engaging said bead, and means for holding said spring in engagement With said head. i

6, EL signal valve device Comprising a easing, a flexible diaphragm `mounted in said easing, a diaphragm plate carried by said diaphragm and having a Chamber, a valve, a valve stem ttor said valve, a head carried `by Said stem and loosely mounted in said Chamber, and a retaining member lia-,ving sei-eiv-threaiiled engagement in said diaphragm plate, for holding `said head in Said chamber. Y

7. A signal valve device Comprising a easing, a flexible diaphragm mounted in said easing, a diaphragm plate Carried `by said diaphragm and having a chamber, a valve, a valve stem for said valve, a head Carried by said stem and loosely mounted -in said chamber, and a retaining member loosely surrounding said valve Stem and having screw-threaded engagement With said diaphragm plate for holding said head in said chamber.

In testimony whereof I have hereunto set by hand. y i i ,CLYDE C. FARMERy 

